An elevator typically comprises a counterweight and an elevator car connected to each other with hoisting ropes. Typically, the elevator further comprises a drive machine having a motor-driven traction wheel around which the ropes pass. The drive machine is usually positioned in a machine room located close to the hoistway in which the elevator car and the counterweight travel.
In cases where a new elevator is installed in a new building, the building cannot always be designed in every way optimal for the elevator. For instance, the size and shape of the spaces available for the elevator are often limited. Nevertheless, the elevator needs to fulfill numerous requirements related to its performance and features. This makes it challenging to design one type of elevator suitable to function efficiently in many different elevator environments. The specific design of the hoisting function, including the drive machine and the rope arrangement, is dependent on the size and shape of the space where the elevator is to be installed, for instance. The drive machine, as well as the ropes, must be fitted in the available space with adequate operating clearances and such that they can be serviced and used safely. The hoisting function must also have capacity to provide an adequately great rated load for the elevator, i.e. an adequate maximal weight that is allowed to be transported. For ensuring the desired capacity, the size of the motor, as well as the power-transmitting components need to be dimensioned accordingly. Adaptability of the hoisting function size, maximum load and dimensioning are important for making the elevator suitable for various installation sites. Especially, modernization of old elevators requires often tailored elevator design, because the modernized elevator design is often very limited by the existing space and structures. Improvements in performance are normally also required for the elevator being modernized. For instance, it is common that the new elevator needs to fulfill numerous modern requirements related to energy-efficiency, space-efficiency, noise, maintenance, safety and economical aspects of manufacturing the elevator.
A drawback with the known drive machines has been that they have not fulfilled the above mentioned various requirements adequately well. Especially, they have not been adequately well adaptable to many different elevator environments in a compact manner with good capacity for load transport. This has lead to need for compromises. For example, in many cases the size of the drive machine has required a spacious machine room or tailoring the structures of the drive machine, the roping arrangement or the machine room in a special and sometimes complicated way. This has been problematic especially in modernization where the machine room of the existing elevator is very low or otherwise tight.